[Feature Request] Support the `explorer.sortOrder` like option

[StrayDragon]

In the current version of coc-explorer, I had tried to check the corresponding options in the documentation, but unfortunately I didn't find it (if it exists, please tell me quietly ... ´ ▽ ` )ﾉ)

I found that the order now displayed in the explorer is lexicographic, but sometimes we want to sort by type, especially in some directories full of configuration file types, like the features provided by vscode

This coc plugin is really awesome, replacing some of my old plugins or key bindings, thanks!

[Rizhiy]

Alphanumeric sorting is also useful.

[ewhac]

The venerable Vim plugin bufexplorer offers several sorting options:

" s : cycle thru "sort by" fields ['number', 'name', 'fullpath', 'mru', 'extension']

Where:

• number: Buffer number
• name: Filename
• fullpath: Full pathname of file
• mru: Most recently used
• extension: Group by file extension.

Of these, I'd most like 'fullpath' and 'extension' options for coc-explorer's buffer list.